Abstract: An electrode catheter includes a metal inner tube with distal and proximal ends and an outer tube formed of a synthetic resin so as to cover the outside surface of the inner tube. The inner tube has a helical slit formed from the distal end to a predetermined position, and one or more insulated wires are laid inside the inner tube from the proximal end to the distal end portion. One or more electrodes are disposed on the outer tube, with the wires extending out of the inner tube through the slit and connected to the electrodes. This electrode catheter possesses high pushability and torque-transmission capability along with a high flexibility and kink resistance, and can be easily inserted into a desired position of complexly branched thin blood vessels without kink or breakage of the wires caused by collapse of the lumen.

Abstract: An accessory pathway detecting apparatus measures action potentials from first and second electrode leads, and outputs the obtained action potentials, as potential maps, to a CRT or a printer such that the action potentials can be displayed in the form of a list. An ablation catheter is inserted and located at a preexcitation portion obtained from the display, and the impedance between each of the electrodes of the first and second electrode leads and the electrode of the ablation catheter is measured by an impedance measuring circuit. A point where the lowest impedance is measured is regarded as an accessory pathway portion. The ablation catheter is fixed at this point.

Abstract: A multielectrode probe of this invention is inserted into a patient when in use. This probe includes a base on which a plurality of signal lines are bonded. Each of the plurality of signal lines has at least one electrode, and these electrodes are arranged on the base with predetermined spacings between them. The electrodes are formed by stripping the isolating coatings of the plurality of signal lines.